Historically, it reminds me of when Muhamad Ali announce he was changing his name from Cassius Clay. A lot of whites felt betrayed when he did that. Same thing with Eminem. He's a white rap artist with a lot of white fans. Now, he's telling them that if they support Trump they're no fans of his. So yeah, the Ali announcement is the closest thing I can recall like this. Either that, or when Dick Clark made that public statement that James Brown wasn't getting treated like other artist "because he's black".

I hope it has a similar impact. Like the impact Ali's refusal to go to war had for instance.